Hi my name is Cesar but ppl call me Ces. I've recently purchased an 07 Mustang GT 500JS. I honestly do not know what the 500JS means except that it comes with a body kit and side exhaust. I joined to get to know more mustang enthusiast and to learn more about the varies options there are out there to make my car the best it can be naturally aspirated. If you have any suggestions let me know. I've recently checked out AmericanMuscle.com and I may go with their programmer. But idk yet.